Process of evaporation, concentration, and distillation.



W. ANDERSON & J. MEIKLE.

PROCESS OF EVAPORATION, CONCENTRATION, AND DISTILLATION.

APPLICATION FILED JUNE3, 1912. 1,056,877, Patented Mar.25, 1913.

VACUUM PUMP man srarns ra rnnr onrcn WELIAM ANDERSON, 0F ELENSBURGH, ANDJAMES MEIJKLE, 0F GLASGOW,

SCOTLAND.

'PROCESS OF EVAPORATION, CONCENTRATION, AND DISTILLATION.

rosasrr.

Specification of Letters Fatent.

Application filed June 3, 1912.

Patented ltllar. 25, 1913.

Serial no. 701,236.

To (17? 201mm 2'1 may concern:

Be it known that we. lVILLLtu Axnrnsox and James Minnie. subjects of theKing of the United Kingdom of Great Britain and Ireland, and residing atHelensburgh, Scotland. and Maryhill. Glasgow, Scotland, respectively.have. invented a, certain new and useful Improvement in Processes ofEvaporation, Concentration, and Distillation, of which the following isa specification.

This invention relates to the concentration, evaporation anddistillation of liquids which may contain animal, vegetable. or mineralmaters in solution, 0. 9., to the evaporation of volatile. solvents fromanimal fats, as in the extraction of soluble substances from bones,evaporation of liquors contain ing sugar, tannin or glycerin, and theconcentration of solutions of caustic soda. \Vhen such liquids aresubjected to the ac tion of heat, especially under pressure less thanatmospheric. it is commonly found that, if the heat be not nicelycontrolled in relation to the pressure on the surface of the liquid,frothing or foaming takes place, and it has been attempted in severalcases to prevent the frothing or foaming as far as possible.

The deliberate object of the present invention is to utilize thisphenomenon as a means of obtaining the liquid in a finely distributedcondition in which condition it will readily be converted wholly or inpart into vapor, the solution being concentrated, or, if the solvent bewholly evaporated, the dissolved matter being leftas a solid residue.

The presentprocess consists in heating the liquid under sub-atmospheric-pre. ure or partial vacuum to convert substantially the entire body ofliquid intofroth or foam, transferring the froth or foam to a secondheating surface, and heating under 'sub-atmospheric pressure the frothor foam so transferred.

An improved construction of apparatus for performing the process 15shown diagrammatically in part side elevation part vertical section inthe figure of the accompanying drawing.

As shown therein, A is a. primary evapo rator which is surmounted by asecondary evaporator B of similar construction. A pipe C connects theevaporator A with a tankl) containing the solution to be treated.

E, F, denote connections for leading a heating medium (e. g., steam orhot oil) to the intermediate tubular sections of the evaporatingapparatus: E, F denote the corresponding return connections.

G is a valved pipe leading from the upper end of the evaporator Bconnected with a suction or vacuum pump H, a condenser being interposedat J.

K, K denote valved by-pass connections from the pipe C to a dryingcylinder L which may be fitted with a conveyor acting as a stirrer andwhich is surrounded by a heating jacket.

M is a valved by-pass connection from the evaporator A to the pipe C. i

N, O. P, Q, and R are the valves.

It will be understood that the sub-atmospheric presure in the entireapparatus, in-

duced by the suction of the pump H, causes the liquid to be drawn intosaid apparatus from the tank D. Said liquid is first heated undersaidsub-atmospheric pressure in the evaporator A and thereby converted intofroth or foam, said froth or foam being constituted bv bubbles eachconsistin of a skin of liquor filled with vapor. The 0am, while stillunconverted into vapor, but. while in a condition to be readily soconverted is separated from the main body of liquid and transferred tothe evaporator B, said trans fer being facilitated by the suction abovereferred to. In the evaporator B the froth or foam is further heated,still under subatmospheric pressure, and parts with a large part of itsmoisture, whereby the solution may be highly concentrated. If it be desired to bring the matter in solution to a state of drynes or toconcentrate the solution still further, the heating of the foam in theevaporator B is-discontinued and the foam is, by the action of the.suction transferred to the cylinder L, where the solution may beconcentrated, or the solvent wholly evaporated. I

What- We claim is:

1. A process of concentrating, evaporating and distilling liquidsconsisting in heat ing the liquid under sub-atmospheric pressure inducedby suction to convert the liquid into froth, withdrawing the froth whilethe same is still unconverted into vapor by said suction to separate thesame from themain My of liquid, and applying with.

tional heat tolthe hot froth so separated while still under saidsub-atmospheric pressure. Y

2. A recess of concentrating, evaporating an distillin liquidsconsisting in drawing the liqui from a suitable source by suction,heating said liquid under the sub-atmospheric pressure induced by saidsuction to convert the li uid into froth, withdrawing the froth w e thesame is still unconverted into vapor by said suction to separate thesame from the main body of J on): McGLmnY.

naines to this specification i'n'the presence of

